December 2010 LSAT Section 3 Question 20

Astronomer: Earlier estimates of the distances of certain stars from Earth would mean that these stars are about 1 bi...

avif on May 24, 2020

Confused

I had a very difficult time with this question. The question stem doesn't give us any information about why the original estimations estimated the star to be so far away. I assumed that it was related to the distance of the star and they had some way of measuring that distance. If that was the case than the fact that bright stars are younger still doesn't explain the fact that the distance is so far away. Regardless of how bright a star is, the light needs time to travel to reach earth which is why estimations of distance are important. Please explain.

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Skylar on May 24, 2020

@avif, happy to help!

This is an intimidating question. It is important not to get carried away in making assumptions based on outside knowledge. Remember, the LSAT is testing your ability to stick to the information offered in the question.

The passage tells us that earlier estimates of how far away certain stars are from Earth would mean that those stars are older than the universe. That would be impossible, so the astronomer sets out to resolve this age-based conflict. The astronomer says that his new estimates place the stars farther away than originally thought, and that the farther away stars are, the brighter they appear. The astronomer then says that this information resolves the conflict between how old the stars are and how old the universe is. It is our job to explain exactly how this information resolves the conflict.

To resolve this age-based conflict, either the universe must be older than originally estimated or the stars must be younger than originally estimated. This would address the conflict between the stars being originally found to be older than the universe. So, we can anticipate that the correct answer choice will include this logic and will also incorporate something from the astronomer's new findings.

(A) "The stars are the oldest objects yet discovered in the universe."
This is incorrect because it does not address the conflict by finding the original estimates about either the universe or the stars to be incorrect. Note that there is a difference between the stars being the oldest discovered objects in the universe and the stars being older than the universe.

(B) "The younger the universe is, the more bright stars it is likely to have."
Again, this is incorrect because it does not address the conflict at hand. We are looking for information that supports either the universe being older or the stars being younger than originally estimated, and this does neither. Finding information to support the idea that the universe is younger than originally estimated only makes the age-based conflict worse.

(C) "The brighter a star is, the younger it is."
This is correct. It incorporates the astronomer's new findings (that the stars are farther away and therefore brighter than originally thought) and combines this with the idea that the stars are younger than originally thought. This addresses the age-based conflict resulting from original estimates finding the stars to be older than the universe by suggesting that these original estimates were incorrect.

(D) "How bright celestial objects appear to be depends on how far away from the observer they are."
This is incorrect because it does not add anything nor does it address the conflict. The passage already tells us that the father away stars are, the brighter they are.

(E) "New telescopes allow astronomers to see a greater number of distant stars."
Again, this answer choice is incorrect because it fails to address the conflict between the age of the stars and the universe.

Does that make sense? Please let us know if you have any other questions!

avif on May 25, 2020

Yes it does. Thanks!